Seat belt buckle sensors are used in vehicle systems for a variety of purposes, such as for providing a safety warning to the vehicle occupants, and setting an air bag system at a proper deployment force associated with a particular seat occupant. Seat belt buckle sensors generally provide an output indicating whether the buckle tongue attached to the seat belt webbing is engaged with the seat belt buckle in a locked condition. This output may be combined with information from other sensors, e.g. a seat belt tension sensor, a weight sensor and/or seat position sensor, to determine whether and to what extent an air bag should be deployed in the event of an accident.
There is a need, however, for a seat buckle sensor that provides accurate and reliable sensing of the buckle condition, while allowing cost-effective manufacture an installation.